In a memo to the Cubs obtained by the Tribune, the agency expressed concern about advertising overkill at Wrigley, which is known for its ivy-covered outfield walls, hand-turned scoreboard and intimate dimensions as opposed to typical corporate billboards at every other baseball stadium.

“It is important that the cumulative impact of new signage in the outfield does not, in itself, create such a defining feature that the historic character of the stadium is altered,” stated the memo, which was obtained through a Freedom of Information Act request.

The NPS says it’s waiting on more information from the Cubs; given that Ricketts wants to start construction as early as next month, he might want to get a move on. (He can always start work before getting NPS approval, but then he’d risk losing the tax credits entirely.) Taken together with the rooftop lawsuit, it would seem to be a recipe for a compromise plan that limits the ad boards (in size, character, color, whatever) to meet both landmarking requirements and NPS preservation regulations, but then, supervillains aren’t known for compromise.